import from drb-2.0.4b3

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@3959 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/drb/timeridconv.rb

@@ -0,0 +1,91 @@
+require 'drb/drb'
+require 'monitor'
+
+module DRb
+  class TimerIdConv < DRbIdConv
+    class TimerHolder2
+      include MonitorMixin
+
+      class InvalidIndexError < RuntimeError; end
+
+      def initialize(timeout=600)
+	super()
+	@sentinel = Object.new
+	@gc = {}
+	@curr = {}
+	@renew = {}
+	@timeout = timeout
+	@keeper = keeper
+      end
+
+      def add(obj)
+	synchronize do 
+	  key = obj.__id__
+	  @curr[key] = obj
+	  return key
+	end
+      end
+
+      def fetch(key, dv=@sentinel)
+	synchronize do 
+	  obj = peek(key)
+	  if obj == @sentinel
+	    return dv unless dv == @sentinel
+	    raise InvalidIndexError
+	  end
+	  @renew[key] = obj # KeepIt
+	  return obj
+	end
+      end
+
+      def include?(key)
+	synchronize do 
+	  obj = peek(key)
+	  return false if obj == @sentinel
+	  true
+	end
+      end
+
+      def peek(key)
+	synchronize do 
+	  return @curr.fetch(key, @renew.fetch(key, @gc.fetch(key, @sentinel)))
+	end
+      end
+
+      private
+      def alternate
+	synchronize do
+	  @gc = @curr       # GCed
+	  @curr = @renew
+	  @renew = {}
+	end
+      end
+
+      def keeper
+	Thread.new do
+	  loop do
+	    size = alternate
+	    sleep(@timeout)
+	  end
+	end
+      end
+    end
+
+    def initialize(timeout=600)
+      @holder = TimerHolder2.new(timeout)
+    end
+
+    def to_obj(ref)
+      return super if ref.nil?
+      @holder.fetch(ref)
+    rescue TimerHolder2::InvalidIndexError
+      raise "invalid reference"
+    end
+
+    def to_id(obj)
+      return @holder.add(obj)
+    end
+  end
+end
+
+# DRb.install_id_conv(TimerIdConv.new)